Offsetting press



A. ZISKA OFFSETTING PRESS Aug. 8, 1933.

Filed March 3, 1932 4 Sheets-Sheet 1 INVENTOR.

Adam Zislz'a .ATTQRNEY. I

w A \I mm mm L Ill III I It OFFSETTING PRESS Filed March 3. 19 32 4 Sheets-Sheet 2 ATTORNEY.

Aug. 8, 1933. A, zl'sKA OFFSETTING PRESS Filed March 3, 1932 4 Sheets-Sheet 3 INVENTOR.

Adam Zislfa BY M fiM ATTORNEY.

Aug. 8, 1933. z s 1,921,210 1 OFFSETTING PRESS Filed March 5. 1932 4 Sheets-Sheet 4 INVENTOR.

Adam Z iska ATTORNEY.

Patented Aug. e, 1933 GFFSE'FCTHNG rat-i i New "i'Z-crii A ncaticn March 3, 1931?.

6 Claims.

The invention relates in general to offsetting presses and in particular to presses for bending strips of sheet metal in the direction oi their width.

In the manufacture of certain curved articles, for example curved side bars for automobile frames, it necessary to provide strips of sheet metal curved in the direction of their width. Such curved strips of metal were formerly punched from sheets of metal considerably wider than the required curved strip. This method of producing curved strips resulted in Waste of the sheet metal as the portion remaining after the strip had been punched from the sheet was of no value other than as scrap metal.

The present invention is directed to an offsettin press adapted to receive a straight, relatively narrow strip of metal and to bend it in the direction of its width to the required curved shape. By such operation substantially all of the material of the original blank strip may be utilized in forming a side bar. Thus the waste resulted from the formerly practiced method of punching curved plates from sheet material is eliminated.

The ofisetting press to which this specification is directed is an improvement over the press covered by Patent No. 1,466,104, granted August 28, 1923, to R. S. Smith et a1, and assigned to the A. O. Smith Corporation. This press is designed to form an element of the assemblage of machines covered by Patent No. 1,397,020, granted November 15, 1921, to R. S. Smith, and assigned to the A. O. Smith Corporation.

An object of the present invention is to provide an offsetting press for bending strips of sheet metal in the direction of their width, so designed that the press may be disposed directly in a production line in which the blanks to.

be offset are advanced laterally.

Another object of the invention is to provide an offsetting press so constructed that the material to be offset may be fed through the press from one side to the other in the direction of the width oi the material.

A further object of the invention is to provide an offsetting press in which the actuating members of the press function in tension and in which the press frame functions in compression in a manner effecting considerable saving in wei ht of the press ad a less costly construction.

Still another object of the invention is to provide an ofifsetting press in which the drive mechanism is disposed beneath the working surface of the press.

{25, 'til'anwatesa, ti/ia, assigncr [5. 0. Corporation, l /iiiwankee, Wis a Cerpc- Serial No. 596,503

The foregoing and other objects of the inven' tion that will be more readily appreciated upon reading the following detailed specification in conjunction with the accompanying drawings may be achieved by the apparatus illustrated in the various views, of which;

Figure l is a plan view of an offsetting press embodying the invention showing the manner in which the material tobe oiiset is fed through the press from side to side;

Fig. 2 is a View in transverse section taken on the plane represented by the line 2-201" Fig. l and showing portions of the press drive mechanism in elevation;

Fig. 3 is a view similar to Fig. 2 taken on the plane represented by the line 3-3 of Fig. 1 showing the feeding mechanism of the press in elevation; and

Figs. 4, 5, 6, and 7 are schematic representations of a transverse section through the press showing the relative positions assumed by the parts thereof in-the various stages ofan offsetting operation.

As shown in section in Fig. 2, the offsetting press comprises in general a relatively heavy frame 1 of substantially rectangular shape, the greater portion. of which is preferably disposed beneath the floor line 2 of the building in which the machine is installed. The upper surface of the frame 1 is substantially level and'constitutes a working bed 3 upon which an oiisetting head 4 is mountedior lateral movement.

As shown in Fig. l, the oifsctting head lextends longitudinally of the working bed 3 and is somewhat longer than the blank 5 of sheet steel to be offset. The press is designed to be set in a production line in which theblanks 5 are advanced successively in the direction of their width. The blanks 5 arrive at the back of the press, which is shown at the. top in Fig. 1, pass into the press without changing their direction of progress, are offset'in the press, and pass out of the press at the front thereof, shown at the bottom of Fig. 1. After being offset, the blanks 5 continue their progress in the same general direction along the production line to the machine which performs the next operation on them.

When a blank 5 to be worked. on is fed into the press, it is engaged by a pair of complementary offsetting dies, the lower die 6 of which is mounted in the upper surface of the bed 3 and the upper die '7 of which is carried in the lower surface of the offsetting head l. The lower die 6 is disposed to engage the lower surface and the forward edge of the plate 5 while the upper die 7 engages the upper surface and rearward edge of the plate. The dies 6 and '7 are shaped to conform, when closed, to the shape of the curved strip to be formed in them. When the blank 5 is fed into the dies, the offsetting head 4 is positioned at the rear of the press and slightly raised to permit the blank to be inserted laterally beneath it, as shown diagrammatically in Fig. 4.

In performing the offsetting operation, the

offsetting head 4 is drawn downward and for ward by eccentric rods 8, one of which is pivoted to each end of the offsetting head and extends in downward and forward direction to embrace at its other end an eccentric 9 on a driven shaft 10 which is journaled in the frame 1 near the end thereof. The downward component of force exerted by the eccentric rods 8 draws the offsetting head 4 toward the bed 3 of the frame and clamps the blank 5 between the portions of the upper and lower dies 7 and 6, respectively, which engage the surfaces of the blank. The forward component of force exerted by the eccentric rods 8 moves the offsetting head 4 forward along the bed 3 and brings the die 7 into engagement with the rear edge of the blank, thus forcing the blank forward into engagement with the front edge engaging portion of the die 6, as shown diagrammatically in Fig. 5.

As the dies 6 and 7 are closed by further forward movement of the o--setting head 4, they are brought to the position shown diagrammatically in Fig. 6, and the blank 5 is bent in the direction of its width to shape conforming to the curved shape of the closed dies. Any tendency of the blank. to buckle or bend in direction other than in the plane of its width is resisted by the downward clamping force exerted on the offsetting head 4 by the downwardly extending eccentric rods 8. To minimize frictional resistance to the forward movement of the head 4 over the work bed 3, the offsetting head is provided at each end with two supporting rollers 11 disposed in tandei i relation.

It'will be appreciated that the force exerted by the eccentric rods in clamping and bending the blank 5 must necessarily be large. To resist this force the eccentric rods and the driven shafts 1O -made of ample dimensions. By reason of the fact that the driving mechanism is disposed beneath the working bed of the machine, the eccentric rods act in tension and the portion of the frame between the driven shafts 10 and the working bed 3 acts in substantially direct compression. With the frame disposed to be stressed in compression, it is possible to construct it of lighter elements than would be the case if it were designed as a C-frame or similar structure subject to tension and bending stresses. As shown in the drawing, the frame is preferably constructed of steel plates out to the desired shapes and welded together.

To enable the curved blank to be removed from the dies at the end of the working stroke, the offsetting head 4 is lifted vertically sufficient distance to permit the foreward edge of the blank to be raised above the edge engaging surface of the die 6. The lifting of the head 4 is accomplished by means of cam slides 12, one of which is disposed beneath the tandem rollers 11 at each end of the press. The cam slides 12 are each provided with working surfaces 13 on which the rollers 11 hear when the offsetting head 4 is in position to clamp a blank in the 6 and 7. To the rear of each working surface 13 of the cam slide 12 is provided an elevated cam surface 14. To effect lifting of the off-setting head 4, the cam slides 12 are moved forward to bring the elevated cam surfaces 14 beneath the rollers 11, as shown diagrammatically in Fig. '1. As a large portion of the down ward force exerted by the eccentric rods 8 on the offsetting head 4 must be carried by the cam slides 12, they are made of rugged construction and are each carried by two anti-friction rollers 15 journalled on the frame 1 at positions substantially beneath the rollers 11 on the offsetting head 4.

The cam slides 12 are each operated by an eccentric rod 16 which is pivoted at one end to 2. depending lug on the cam slide and which embraces at its other end an eccentric 17 on the driven shaft 10. As indicated diagrammatically in Figs. 4 to 7, the eccentric 1'7 has a somewhat larger throw than the eccentric 9 and is disposed on the shaft 10 to lag the eccentric 9 by approximately 90.

As shown in Fig. '7, the offsetting head 4 starts to move in the rearward direction as soon as the cam surfaces 14 of the cam slides 12 are moved under the rollers 11. As rotation of the shaft 10 continues, both the offsetting head 4 and the cam slides 12 are moved rearwardly, with the movement of the cam slide 12 lagging the movement of the offsetting head in such manner that the cam surfaces 14 remain beneath the rollers 11.

When the offsetting head 4 arrives at its extreme position at the rear of the press as shown in Fig. 4, the cam slides 12 have not yet moved to their extreme rear position and the offsetting head is held in raised position by the cam surfaces 14 which are still in engagement with the rollers 11. It is while the offsetting head is held in raised position in this manner that the rectangular blank 5 to be offset is moved beneath the working head into engagement with the die 6.

Upon further rotation of the shaft 10, the

cam slides 12 continue to move rearward and the offsetting head 4 starts to move forward. This relative motion in opposite directions causes the rollers 11 to roll from the cam surfaces 14 on tothe working surfaces 13 of the cam slides 12 to the position shown in Fig. 5

in which clamping force is exerted by the offsetting head in downward direction upon the blank 5. As the offsetting head 4 moves forward in the working stroke to the closed position shown in Fig. 6, the cam slides 12 are also moved forward but lag the movement of the offsetting head to such extent that the cam surfaces 14 remain somewhat behind the rollers 11. When the offsetting head 4 arrives at the end of the working stroke, the cam slides 12 continuerin their forward movement to bring the cam surfaces 14 beneath-the rollers 11 and lift the offsetting head 4 to open the dies 6 and '7.

While the offsetting head 4 is in the raised position, the curved blank 5 is dislodged from the lower die 6 by a plurality of knock-out pins 18 which engage the lower surface of the blank at points distributed throughout its length. Each knock-out pin 18 is carried by a cross head mechanism 19 slidingly mounted for vertical movement in the frame beneath the working bed 3. At the lower end of each crosshead 19 is provided aroller 20 disposed to cooperate with the surface of a sliding cam bar 21. Each cam bar 21 is pivotally connected to a lei-i) link 22 which is pivoted at its other end to an arm 23 depending from a shaft 2e journalled longitudinally of the frame 1. shaft 24 is connected by an arm 25 and a link 26 to the depending lug on each of the cam slides 12 in such manner that the cam rod 21 is actuated in direction opposite to the direction of move ment of the cam slide 12. As may be seen in Fig. 3, when the cam slides 12 are movedto the forward position to elevate the offsetting head 4, each of the cam bars 21 is moved to its rear" ward position in which the roller 29 of each cross-head 19 engages an elevated cam surface 27, thus moving the cross-heads upwardly and forcing the knock-but pins 18 into engagement with the lower surface of the blank 5 to lift it "ally from beneath to draw it forward from beneath the offsettin head 4. p

of the slides is actuated b an o c llating arm 30 pivotally mounted at t rward end of the slide 28. The oscillating rm 30 is mounted rigidly on a short shaft 32 journalled in the frame 1 and carrying an arm 33 which is driven by a connecting rod 34 actuated by a crank pin 35 on the inner end of the driven shaft 10. The crank pin 35 is so related angularly to the eccentrics 9 and 17 that the slide 28 starts to move forward just after the offsetting head 4 is raised and the blank 5 dislodged from the die 6 by the knocloout pins 13.

As the slides 28 move forward, feedin triggers 36 near the rear end of each slide engage the rear edge of a rectangular blank 5 and draw it forward underneath the oifsetting head 4 while the head 4 is moving to its position at the rear of the press. While the oifsetting head 4 is moving forward in worl stroke, the slides 28 move to the rear to be in position for ejecting the curved blank and for feedlo the rectangular blank into the p s. L s 29 and 36 are pivotally mounted on the $1-465 28 in such manner that they may be depressed while passing beneath the blanks during the rearward movement of the slides.

The reciprocating slides 28 may be made of any convenient len th and any number of trigges may be mounted on them for advancing the blanks, as illustrated by a trigg r 37 on each slide near the front of the p ess which en ages the curved blank 5 on the ne: troke after i has been ejected from the die 6 and carries it forward and out of the press. in some instances, it may be desirable to extend the reci'rocating slides 28 both forward and rearward of the press to constitute a conveyor system for advancing the blanks laterally from a loading station, through the offsetting p forward to the next machine v 1 ttes upon the blanks.

The driven .ts i=3 which drive the recipthe press are comparatively rocating parts of shortshaits journalled in axial alignment in each end of t e frame 1 in substantially the horizontal mid-plane of the frame. As shown in Fig. 1, each shaft 10 is provided with a relatively large gear wheel 38 meshing with a pinion 39 securely fastened on a counter-shaft 40 extending longitudinally of the press also in the mid-- plane of the frame, and which serves to synchro nize the operation of the two driven shafts 10. At the middle of the counter-shaft 40 is mounted. a large gear wheel 41 that meshes with a pinion 42 011 a driving shaft 43 which extends l ngitudinally of the press in the mid-plane thereof occupied by the countenshaft 4i) and the shafts 10. At one end of the driving shaft 43 is a suitable friction clutch 44 by means oi which the shaft may be connected to a driving motor 45. At the other end of the shaft 43, a suitable brake mechanism 46 is provided for stopping the press holding it in fixed position after it is stopped.

In order'that access may be had to the dies 6 and 7 to inspect or change them, means are provided for causing the forward edge'of the offsetting head 4 to pivot upwardly about the rear rollers 11. This is accomplished by temporarily connecting the ends of arms 47 which are carried by standards 48 at the-rear or" the pr to lugs 49 on top of the oifsetting' head 4. With the offsetting head 4 at the rearmost'position in its stroke, the openings in the ends of the arms 47 and in the lugs 49 are brought into alignment and suitable bolts or pins passed through them. The shafts 10 are then turned to move the oifsetting head forward, but as the top portion of the head is restrained from forward movement by the arms 47, the head is caused to rotate relative to the ends of the arms 47 and as the rear rollers 11 are advanced along the cam manner that they may be removed readily from the working bed or the offsetting head in the event it is necessary to repair them or to substitute other dies.

Although one specific embodiment of the invention has been described in some detail, it is to be understood that the terms used are terms of description and not of limitation and that others skilled in the art may make embodiments of the invention differing in design from the embodiment herein described without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In an oifsetting press for bending a strip of sheet metal in the plane of its surface, a base having a substantially flat working surface, an offsetting head longer than the strip to be bent disposed on the working surface, means for feeda strip to be bent laterally from the rear of the press, means for moving the offsetting head to clamp and bend'the strip, and means for removing the bent strip laterally to the front of the press.

2. An offsetting press for bending a strip of sheet metal in the direction of its width, comprising a working bed, a die for engaging one face and one edge of the strip to be bent mounted on the working bed, an offsetting head mounted for lateral movement on the working bed, a compl mentary die carried by the head for engaging the other face and the other edge of the ilid strip to be bent, an eccentric rod attached to each end of the head extending downwardly and forwardly, and driving mechanism mounted beneath the working bed associated with the eccentric rods for exerting a downward and forward force on the offsetting head to clamp and bend the strip of sheet metal.

3. An offsetting press for bending a plate of metal in the plane of its surface, comprising a frame having a substantially level working bed, an offsetting head mounted for lateral movement on the bed, means for feeding a plate in lateral direction from the rear of the bed to a position beneath the offsetting head, complementary dies on the bed and on the offsetting head respectively, driving means mounted in the frame beneath the bed and connected to exert a downward clamping force and a forward bending force on the offsetting head to clamp the plate in the dies and to bend it, mechanism within the frame for raising the offsetting head at the end of its Working stroke, means for lifting the bent plate from the die in the bed, and ejector mechanism for removing the bent plate laterally from the die to the forward edge of the press.

4. An offsetting press for bending sheet'metal comprising a bedfor receiving the sheet metal, a die for engaging the sheet metal to be bent mounted on the bed, an offsetting head mounted for lateral and vertical movement relative to the bed, a complementary die carried by the head cooperative with the die mounted on the bed for performing a bending operation, and actuating mechanism mounted beneath the bed for operating the head and head die to clamp and bend the sheet metal.

5. An offsetting press for bending sheet metal comprising a bed for receiving the sheet metal, a die carried by the bed, a head mounted for lateral and vertical movement relative to the bed, a complementary die carried by the head cooperative with the bed die for bending the sheet metal, and actuating mechanism mounted beneath the bed and connected to the ends of the head and head die for operating them to effect the bending operation, said actuating means being so disposed that the sheets to be operated upon may be moved through the press from rear to front and discharged.

6. An offsetting press for bending sheet metal comprising a bed, a die for bending the metal carried by the bed, an 'offsettng head mounted for lateral and vertical movement relative to the bed, a complementary die carried by the head, actuating mechanism mounted beneath the bed connected to the head, said head being pivotally mounted at one side, and means provided on the head to be connected to the actuating mechanism to rotate it about its pivot point to give access to the dies.

- ADAM ZISKA. 

